Friday, May 29, 2009

Road-Trip Part 3: All About Cedar Gnats

I’ve already mentioned how the rainy weather was a mixed blessing, in that it led to the change of plans that took us to the mysterious Chacoan-style ruin on the Ute Mountain Reservation. But it turned out to be a boon in another regard as well. On the drive back from the hike in the tribal van, I chatted a bit with 2 women (both Cortez locals) seated next to me. I mentioned how sketchy the weather was, and they pointed out that I should be glad because the rain and cold had driven away the Cedar Gnats. They went on to say how this is one of the worst/earliest gnat seasons they can remember. Sure enough, our camping experience that evening was gnat-free.

Tangent: Nice as they were at first, I began to suspect later on during the ride that my seatmates were a few spokes short of a true wheel. I overheard them talking about UFOs and how the international space station crew had been forced to shut off their 24x7 external cameras because it had become too time-consuming to edit out all of the UFO-filled frames before passing along the feed to Earth-bound viewers below.

Nested Tangent: This is as good a time as any to share one of my half-baked theories: Why Otherwise Reasonable People Believe Weird Stuff. I don’t mean like crazy people who think God is telling them to kidnap child-brides. I mean otherwise normal people who believe that aliens regularly visit the Earth to mutilate cattle and impregnate rural people, or who pay to visit “psychics”, or who think evolution is bogus because it’s “just a theory”, or who believe that enviro-liberals cooked up the whole global warming thing so that government could “have more control” over people.

Lots of smarter folks than me have weighed in on this topic- Michael Shermer*, the Editor of Skeptic Magazine, even wrote a book entitled Why People Believe Weird Things. But that never stopped me before from coming up with a half-baked theory of my own, so here’s mine: Because they’re fearful, lazy, or both. People believe weird stuff largely because they lack an understanding of the function, wonder and beauty of the natural world. And because they don’t understand how the world works or how fantastic and beautiful it is, they see it as cold and strange and ugly and scary, and so they turn to stories that seem to provide explanations and excitement and meaning and wonder, when the truth is that if they just spent a little time and effort and attention to understand the real world, they’d see that excitement and beauty and wonder are all around them right now.

*Shermer is also a former bike racer who had a hand in the design of modern-day bicycle helmets.

When people who don’t know much about the desert learn that I like to camp, bike and hike in Southern Utah, they often ask me whether I’m worried about various creepy-crawlies, including scorpions, rattlesnakes and tarantulas. They want to know if I’m afraid of them (I’m not), whether I might step on them (probably not), or if they ever crawl into my sleeping bag (no.) None of these critters worry me. The one critter that does worry me, they never ask about- gnats.

If you’ve ventured into Southern Utah between late May and July 1, you know exactly what I’m talking about- those little “midges” or “no-see-ums”. They’re always right there, hovering around your eyes and ears, driving you crazy. And when they bite, their evil little wounds somehow itch worse than any mosquito bite*.

*And they always seem to get me on the ears, where mosquitoes almost never bite, and those ear-bites just itch like crazy…

Growing up in New England, I had lots of experience with mosquitoes and black flies. While both are annoying, they’re at least big enough to see, and so you stand a chance of killing them. But Cedar Gnats are so tiny as to be quasi-invisible; you wave and swat, but you almost always miss them.

On our last day the weather improved, and we stopped for a hike in Hovenweep National Monument (pic right). And for the first and only time of the long weekend, we finally encountered gnats. Not many, but enough to be aware of. And as we hiked between the fantastic ruins surrounding a large arroyo, I thought about gnats, and realized that I wanted to know 4 things about them:

1- What are they?

2- Why are they biting me?

3- Why are they only a problem in late Spring/early summer?

4- Why are they only here?

This post is what I found out.

What Are They?

Biting Midges occur world-wide. There are thousands of species in the family Ceratopogonidae (blood-sucking flies), some 500-1000 of which (depending on who’s counting) belong to the genus Culicoides. Most midges/gnats are found in wet or semi-aquatic climates, but a smaller number have adapted to more arid environments.

What we call Cedar Gnats in Southern Utah are specifically 9 different (maybe more) species of Culicoides. They hatch in (non-flying) larval form from eggs laid in Spring or early Summer in fissures in the bark of Utah Juniper trees, and crawl around the fissures eating plant debris and algae. The larvae overwinter in the bark fissures until the following Spring when they pupate (like what a caterpillar does to become a moth or butterfly) into flying adult gnats. (Graphic not mine)

The males typically emerge first, and wait around for the females to appear. Mating often occurs at the site of a blood host, shortly after the female has fed.

Tangent: Here’s something cool- a number of Culicoides species are parthenogenetic, meaning they have no males. Alas, I’ve been unable to determine whether any of “our” 9 species are parthenogenetic. The parthenogenetic females still require a blood meal to produce eggs.

Why Are They Biting Me?

Adult Culicoides gnats don’t typically eat blood, but rather subsist on nectar, and in fact they serve as pollinators for some flowers. But the female requires a blood meal to produce eggs (just like mosquitoes) and she seeks a vertebrate* from which to obtain it. So far, this sounds pretty much like the deal with mosquitoes. But here’s where it gets different.

*There are indications that she may hone in on CO2 exhalations to do so.

A female mosquito pokes a teensy hole in your skin with its specialized proboscis, injects a bit of anti-coagulant, and then sucks up your blood through the same organ. The itching you experience is a reaction to the anti-coagulant.

But a Cedar Gnat uses its mandibles to actually saw a hole in your skin, then spits anti-coagulant onto the wound, and then sucks up the pooling blood with its non-piercing proboscis. It’s a sort of more “violent” wound, and this may be why their bites are so much more annoying (and lasting) than those of mosquitoes.

The bites aren’t really harmful to us, with the important exception of people who experience an excessive allergic reaction to the anticoagulant. But they are dangerous to both livestock and wild animals, including horses, cattle, deer and pronghorns, as they serve as a transmission vector for several pathogens, most notably the Bluetongue virus*.

*This one affects only ruminants, not humans.

Horses, in particular, also suffer a much worse allergic reaction than us to the anti-coagulant, a condition known as “Sweet Itch”, which can result in severe skin irritation and hair loss.

Side Note: But in other parts of the world, including Central and South America, biting gnats are transmission vectors for a number of human pathogens, including filarial worms.(Elephantiasis is caused by a type of filarial worm, or more correctly, nematode.)

Why Now?

Between May 15 and June 15 is when they pupate, mate, feast and lay eggs, up to 100 in a batch. Some Culicoides species lay 2 batches of eggs.

Why Are They Only Here?

The thing that always bugged me about these little guys is, why aren’t they in town? By which I mean that you can be out and about in Canyonlands or Arches (pic right = Twin A & me in Arches NP) or on the Slickrock Trail and the gnats will be driving you bonkers, but if you go into a town in the same area/climate, like Moab or Blanding or Cortez, they completely disappear. Why should this be? If they’re so hot for a blood meal, why don’t they zip into town, where there are people (and pets) galore to feed upon?

Because they’re lousy fliers, with a typical range of no more than 300 feet from their hatching tree, and generally Utah Juniper (pic left) doesn’t occur in the middle of a town.

Tangent: There’s still an unanswered question for me though. I can’t swear to it, but I’m almost certain that I’ve been plagued by gnats in open desert/shrubland, when I’ve been well over 300 feet from the nearest Juniper. Either I’m mistaken (always possible), or their range is greater than 300 feet, or they’re able to nest/hatch in the bark of shrubs, such as Sagebrush or Rabbitbrush or Shadscale… I’ll have to pay closer attention on my next encounter…

The easiest way to deal with the gnats is simply to avoid the desert for a month or 2, but late May is otherwise one of the most pleasant times in Southern Utah. Mountain biking in particular is a tricky undertaking. So long as you’re rolling, all is wonderful. But stop for a rest, or a mechanical, and they’re all over in under 30 seconds. Of course they disappear shortly after sundown, but that leaves the issue of what to do with the 16 hour days we currently enjoy…

Tangent: Years ago, I did a solo mtn biking/camping trip in mid-July up on Boulder Mountain. The mosquitoes were unbelievable. On my last ride, I did a 10-mile singletrack out & back- 5 out, 5 back. At mile 9- a mile from the car- I flatted. I had to make a split-second decision: change the tube, or run with my bike for a full mile. I chose the former. I kept my cool, but just barely. With my hands busy, dozens and dozens of mosquitoes feasted on me. Had I flatted a second time (or screwed up the repair) I almost certainly would’ve dropped the bike and run for it.

If you do go desert camping or backpacking in gnat season, the toughest part is sitting around camp. Here are the 2 pieces of protective gear I recommend you bring.

2- Head-net. Yes, it looks dorky. After about an hour you won’t care. Arizona Steve and I bring these on every Spring backpack trip. They’re particularly valuable when your hands are busy – cooking for example. We’ve even eaten dinner with them on, raising the lower elastic ring to the “moustache-line” between mouth and nose.

So that’s the deal with those gnats. Me, I’m done with the desert for a few months, so I won’t tangle with them again anytime soon. I think.

45 comments:

That's a big ol' YES to the face-nets. I've heard a story of one group of people who went into the centre of Australia, some with nets, some without (we all had nets when I went). The beginning of the first day, those without nets laughed at those wearing them. By the end of the day, they were down on their knees, begging, pleading, for the love of all that is holy, please, please, please can I borrow your net for just five minutes? Central Australia doesn't have much in the way of gnats, but the sweatflies are insane.

Anon- thanks for the comment. Your feedback- worst season in several years, gnats showing up 2 weeks early- was exactly what the locals over in Cortez were saying. You're lucky to live where you do, but this sounds like a trying month or so for you.

As it turned out I *did* get to experience them one more time this season, yesterday, when I was down in Canyonlands. They were formidable, but the winds were kind to us.

Thanks for Biology.I camped & rode mtn bike on Gooseberry mesa last week and earlier @ sedona, both places I was preyed upon mercilessly.Question: Are some people tolerant to bites in that no welts or other skin reactions? Mosquitoes leave no mark on me.I will link your page on mine for this lessonJP Nuts

JP- For mosquitoes (and I assume gnats) the answer is definitely yes- some people experience much worse reactions to bites than others. Not only that, but people have varying degrees of “attractiveness” to mosquitoes (and again, I assume gnats.) An interesting paper exploring these topics through a 7 year study of Australian twins can be found here. (The paper also cites earlier research which you can probably track down if interested.)

On a personal note, mosquito bites almost never last longer on me than about 2 hours, but they remain for 1 or 2 days on my wife’s skin.

I read your Gooseberry post and you have my sympathies; I imagine the gnats were ferocious there last week.

Thank you SOOOO much for your wonderful information about cedar gnats. My husband and I went to an outdoor wedding on 6/13/09 @ 10am in Sedona, AZ. We were bit massively, until back in the car. The bride/groom were swatting them through the entire cemermony...LOVELY! On 6/14 we went to Jerome, AZ - same thing! 3 days later we are still living off of Benadryl pills and cream! My husband is never bit by mosquites, just me! Now he knows what such a reaction feels like, but you are right, these critters are WAY worse than mosquitos! Thanks again for your great documentary. I am now assure that they aren't bug bites from the hotel!

HiGreat article with good information.Ilive in Apple Valley just below Gooseberry Mesa and have to suffer the ravages of the gnats every spring. My question is: Is there any good repellent that works against Cedar Gnats. We use Avon Skin so Soft out of desperation, but it only keeps the gnats from biting once they have swarmed your skin. A messy ordeal. Products with Deet have absolutely no repellent affect. HELP !!! ThanksBruce

Bruce- thanks for your comment. I'm sorry to say, no, I don't know of a good repellent, and have likewise found DEET to be ineffective. I haven't yet tried the garlic strategy (see this post) with gnats, but seeing as you're around them everyday, even if it did work, it would represent a, uh, significant commitment to a garlic-based diet.

I think you live in a place that's pretty close to heaven (I'm a frequent visitor to Little Creek and Gooseberry) but if I lived there myself I imagine I'd spend a month a year wearing my headnet.

I just got back from Pilot Ridge in the Grand Staircase of the Escalante with about 40 bites on my body, mostly on my face and head! I wish I had a head net while I was there. I was also hoping someone had a suggestion for a repellent that works on the no-seeums. I guess I will be buying ahead net soon. The spf 30sunscreen I was using seemed to repell better than 'OFF' bug spray.

WHEW...thank you for this! no one i talk to here in slc knows what i'm talking about! even at rei! the only question i have about these gnats is why do you say they go away at dusk? they go right thru my truck camper's noseeum netting and bite me all night long. i had to check into a hotel to get some sleep. but last night i discovered that a large piece of bridal vail fabric layed over my head actually works, as long as i have a fan blowing air at my head for ventilation. and now something new: they have invaded my office bldg as of 8:10pm tonight. i've been in slc since may 10 2007. why is this the 1st time i've experienced this? where can i go truck-camp to get away from them at night? i was truly desperate there until last night's bridal vail discovery. would still love to be free of them, tho.

I have been looking for several days on info on these bugs... my grandparents live in southern Colorado it is a very desert like area they also have these pests and my grandma is severely allergic to the bites. I have been trying to find help from someone but even the dr's look at us like we are nuts! The best we have found to detract them so far is spraying her with cider vinager rather then bug spray, we were told that citranella is an attractant not sure if thats true or not? Is there any plants that we can plant near her home to run them away?

My granddaughters who live in the St George Utah area have many many bites on their legs, arms, face. They live out in the country (Dammeron Valley) where there are lots of juniper trees. The only thing that has helped the itching is anti-itch cream and benedryl. Any other suggestions?

I live in Sedona and the Cedar Gnats arrived with a vengence about a week ago. Turns out I'm highly allergic to their bite. and one bite lasts at least 5 days. The bite area gets inflamed and quite hot and swollen, but a wise friend slathered me with aloe vera and the symptoms subsided noticably.

I arrived last week to the Kanab area for my first visit. The Gnats must have known I was 'fresh meat' because they attacked me immediately. I must be allergic to them because all of their bites are red and swollen. At certain times of the day it seems all of the bites itch at one time. I wash my arms down (heavily bitten) with rubbing alcohol, then apply 'Corn Huskers Lotion'. This does give relief to the itching and does not leave an oily residue on the skin. I have been searching for treatments but have not found anything that works for me. Maybe this info will help others.

I have been bitten all over my head, ears, face and arms this last weekend. Besides the obvious swollen, red, ozzing & never ending itching, I have swollen glands and headache and feel really lousy. Has anyone else ever experianced a reaction like this with the cedar gnats.

I have had good results withdeet put only the 98 - 100% kind. Lower concentrations are ineffective. I scrunch my eyes closed and srpay my head and arms completely and thoroughly. Don't wear shorts either.I kind of like the naked lady mudflap socks.

I've lived in Sedona for 33 years. The nasty, evil, rotten little buggers, otherwise known as no-see-ums, become a problem here in early May when it first starts getting warm - and end about the time the monsoons arrive - early to mid-July. Skin-so-soft keeps them off, but it also repels humans. I stay inside for those two months. Some years, my bites are really nasty and other years they don't bother me as much. I can guarantee that Sedona's Chamber of Commerce doesn't tell you about no-see-ums! Interesting that they don't stray far from their birth tree. Thanks for your info!

I live in Boulder, Utah and we have gnats. I haven't found anything to repel effectively (lots of talk about Skin So Soft, deets, etc, but I have found repellent very limited effectiveness.) However, I have discovered one thing that really helps me. Carry calamine lotion. As soon as the bite starts to itch, put a small dab on it. Do not scratch these bites!! They will last a week or two if you scratch, break open, etc. But resist scratching (calamine will relieve the urge in about 10 minutes or so) and the bite will receed quite rapidly.

This thread is great as I am so relieved to know I'm not alone in being one of the unluckies whose cedar gnat bite results in a temporary "Frankenstein" look. My bites swell and ooze and I look like a freak. I also seem to be the only one in my group who ever has this problem. The only thing that has brought some relief for me is benadryl gel but I usually don't have it out with me and by the time I get home it's too late. I live in Moab and get bit regularly when out hiking at Arches or somewhere nearby. My most recent experience was yesterday so they are already out! I will look forward to seeing if any one finds a good repellant.

Great info in this post about these nasty little pests that nobody seems to know much about (or admit to it anyway). We live in CO and went to Sedona for the first time from May 29 - Jun 3, 2011. We rented a house in Sedona and went hiking often. The house had large Junipers on the property. We were bitten by these gnats both at the the house and on the trail.

A few notes about the varied reactions of different family members. My wife reacted the worst. The bites became inflamed immediately and were very itchy. Calamine seemed to be the only thing that provided much relief. For me, the initial small red bite was all that you could see. The next day, the bites were surrounded with a perfect red circle the size of a pencil eraser, but no itching or discomfort at all. The red circle went away in another day. However, after arriving back in CO almost a week later, the bite sites swelled and started itching like crazy! The anticoag that these guys inject must be some pretty potent and long lasting stuff!

We loved the Sedona area, and will definitely go back...just not between May 15 and June 15!

We live in the Winchester Hills area north of St. George, Utah. These gnats have been miserable here for the past couple of weeks. My husband and I were both covered with bites around out hair and face. Also arms. So intensely itchy that they were driving us crazy. I read somewhere that you could boil a little water in a pan on the stove, then use a cotton swab to dab a drop of the boiling water ever so lightly on the bites. It does sting a little when you first touch the swab to your skin, but the burning sensation is a great relief compared to the itch, and it works better than anything else that we tried. It honestly seemed to relieve that itching for several hours. It worked for us.

I wet and wring out a handtowel and wear it draped over my head when I have to go outside during the dreaded month of June. It looks REALLY COOL, even cooler than the net hats but serves a dual purpose of keeping them out of my ears and keeping me cool at the same time. For me if I can keep them away from my eyes and ears I'm good but I think I'm building up an immunity to the bites after 14 years in Mancos, CO - And no, I have found no truly effective way of repelling the little devils. I truly believe that Skin-So-Soft only works because they drown in the oil before getting a chance to bite you.. My mom once sprayed herself with Pam cooking spray, in desperation, to a similar effect. She was just greasy and covered in lil black dead gnats - yummy!And yes, if you can keep moving or if there is even a slight breeze you are probably okay but things like watering the garden, a normally pleasant chore, become a hellish nightmare!

Thanks for the biology lesson. I ordered Crocodile repellent from Scotland (land of midges) and it was fairly (although not totally) effective. Way better than deet. Head nets and spraying the sockline helped also.

Although I can’t find very much information on Cedar Gnats I did find piles of data on Mosquitoes. The anticoagulant that is found in their saliva is a type of protein. So it stands to reason that Cedar Gnats would be as well. When scuba diving in Mexico every diver keeps a jar of UNSEASONED MEAT TENDERIZER in their bag for sting rays. The venom from the sting is a protein as well, thus the remedies of extremely hot water, ammonia or meat tenderizer. The idea is to break down the proteins in the venom or in this case the anticoagulant. While hunting in the Sedona area I became the unfortunate dinner for seemingly millions of cedar gnats. After a day or two of digging and scratching I started looking around on the internet and came up with this. Make up a paste with unseasoned meat tenderizer and rub it on the affected area (the gritty texture feels pretty good on the itching) and then leave it on your skin for a half hour or so. For me this worked better than anything else I tried and in most cases it worked in the first application.

THANK YOU! I have been searching for information on these since I got bit a few nights ago, all over my head and neck and chest in our home. The next night it was my arm. I found two little buggers (they looked so harmless) floating in my bath water the next morning after dunking my head. May need to keep the windows closed (hate that) and the AC on all season in our home in St. George UT. SO GRATEFUL for this post! The Wallgreens pharmacist looked at me like I was crazy and sent me to the delouser shampoo. Seriously? and he LIVES here! THANKS AGAIN!!

I live in Moab, The no see ums are hardly even out this year. Maybe because it's so dry. I spend hours out every day up at Slickrock, so I notice things like that. I usually have to wear a bug net, but not this year (2012).

I'm one of those people who they don't bite, but they get in my nose and eyes, thus the net. They drive my dogs crazy. The worst I've ever seen was in Scotland.

I've also lived in Green River, UT, where there really aren't any cedars, and the dry bone desert out there (Mancos shale) can be thick with them, as bad as anyplace with junipers. So where they live out there, no idea, but they're there.

Wanna get rid of cedar gnats? I know it sounds weird but I promise it works... Burn horse or cow shit..gets rid of them every time...add sage for the smell of you like. Only thing I have ever tried that actually works and way better than any chemicals

I've lived in St. George for 5 years but have not suffered from the cedar gnat's biite until yesterday. This post confirmed my suspicions that those annoying gnats that bothered me while hiking yesterday are the cause of today's oozing and swollen welts. Hard to believe what those little buggers can do. The itching is terrible, and they bit my ankle and the back of my head.

We live in Apple Valley,UT which is about 12 miles east of Hurricane andhave been living with the seasonal Gnats for 13 years. Have tired several repellants containing DEET which had absolutely no deterrence.

Anyway, finally tried some Off Clean Feel repellant with 5% Picaridin (not DEET).This stuff seems to be very effective keeping the little buggers from biting you, although they still swarm. It has been the only repellant we have found to be evenremotely effective.There are several brands using picaridin with up to 20% concentration. Go to Amazon and put in "insect repellant picaridin"Good luck and report back your results.CheersBruce

Excellent article. I'm building 10 miles east of Kanab and have been plagued by gnats for years. Never tried a repellant but I swear by "Preparation H" reduces the itching and reduces swelling. Martin.

Excellent article. I'm building 10 miles east of Kanab and have been plagued by gnats for years. Never tried a repellant but I swear by "Preparation H" reduces the itching and reduces swelling. Martin.

More KUDO's on your great research! I've lived in the Sedona area for 28 years & have always lived on the fringe. So the cedar gnats are the bane of my existence! They prefer me over others, as I have a fast metabolism (more nutrients per drop of blood). And I react pretty badly. I don't think one becomes immune; I haven't. One repellent that works for me is Cutter's Outdoorsman (smells like dirt). Once bit, I use Chiggerex Plus (from Walmart). It's really important NOT to scratch these bites! Just apply the Chiggerex gently & leave alone.I too have noticed they stray farther from the Junipers. I've also read they breed in slightly moist dirt at the base of the trees, maybe shrubs too. And they sometimes last from May (first few 80*+ days) well into August here!I sometimes wonder if they are adapting to & carrying other pathogens. Things like Hanta virus or Lyme or West Nile virus. Any studies about that?

Old thread but I though I would put my 2 cents in. Well, only 1 scent really.

Here in Wisconsin we have some gnats, not near as bad as I have found in the Moab area but they do bite. I was badly bitten by cedar gnats in the San Rafael Swell and western area of Canyonlands. The swelling and redness came and went for a full year after! I don't much like cedar gnats..

We find that vanilla extract helps a lot to keep them away. You have to re-apply every half hour or hour but it does work on our Wisco gnats. Hopefully I will not get to test vanilla on the gnats when I return to the area this year.